Interpretive Summary: There are two primary concerns when pigs are fed diets with high concentrations of dietary fiber: 1) lower energy content and 2) increased fecal output. Diets for pigs which contain high fiber content have lower energy content than typical corn and soybean based diets. The energy available for the pig from the fiber components comes from bacterial fermentation of the fiber in the large intestine. This fermentation produces short chain fatty acids that the pig can absorb. The absorbed fatty acids are then used for energy by the pig. Fecal output is increased when pigs are fed high fiber diets. If feeding a fiber fermenting bacteria to pigs resulted in greater fiber digestion and decreased fecal output it would be very beneficial in pork production. We gave pigs three fiber fermenting bacteria fed both conventional corn-soybean and high fiber diets. Pigs given one of the bacteria had increased fiber digestion and decreased fecal output. Additionally, these animals had elevated plasma cholesterol and glucose concentrations indicating an improved energy status. This is the first report of giving pigs a fiber fermenting bacterium, which has improved fiber digestibility and energy status in the pig as well as decreased fecal output. Successful application of this bacterial treatment would improve pork producer's profitability.

Technical Abstract:
Inclusion of feedstuffs with higher plant cell walls (fiber) content in swine diets has increased in recent years due to greater availability and lower cost, especially by-product feeds such as corn distiller’s dried grains with soluble (DDGS). Limitations of feeding higher fiber diets include increased fecal output which can exceed manure storage volumes and decreased energy density which can decrease growth performance; dietary treatments which ameliorate these limitations would benefit pork producers. Forty-eight grower pigs (61.1 kg initial BW) were used to establish the effects supplementation of fiber fermenting bacteria in a 2 × 4 factorial consisting of 2 diets (standard and high fiber) and 4 bacterial treatments (A, no bacteria, and B, C, and D bacterial supplements). The increase in fiber came from inclusion of soybean hulls (10%) and corn DDGS (20%) in the diet. The three bacterial supplements (all Bacteroides strains) were isolated from fecal enrichment cultures and selected for their fiber fermenting capacity. The high fiber diet increased fecal output, blood cholesterol and triglyceride concentrations, and digestibility of NDF, ADF and sulfur; CP digestibility was decreased (P = 0.10). The improved fiber digestibility and altered energy status of the pigs fed the high fiber diet was primarily due to fermentation of the soybean hulls resulting in increased short chain fatty acid production and absorption and decreased dietary starch content. Overall, the pigs fed the bacterial treatments had only increased blood cholesterol concentrations (P = 0.10). When the individual bacterial treatments were compared, pigs fed bacteria B had decreased fecal output (P = 0.10) and both blood glucose and cholesterol concentrations were elevated (P= 0.10) compared to the other three treatments, indicating an improved energy status. Pigs fed bacteria B increased both CP and ADF (P = 0.10) and tended (P = 0.16) to have increased NDF digestibilities compared to pigs fed no bacteria (treatment A). While pigs fed the other two bacterial treatments did not differ from pigs fed bacteria B for nutrient digestibility, both had similar fecal outputs to pigs fed no bacteria. This is the first report of reduction in fecal output and increased fiber digestibility with pigs fed a live bacteria. Successful application of this bacterial treatment could result in improved pig performance and decreased manure volumes, both of which would improve producer’s profitability.